1. Field of the Invention
This invention relates to a dual-mode electrical plug, more particularly to dual-mode electrical plug having a ground prong that is movable between an extended position and a retracted position.
2. Description of the Related Art
FIGS. 1,2 and 3 illustrate a dual-mode electrical plug of ROC Patent Publication Number 200618417. The dual-mode electrical plug comprises an insulating body 11, a pair of conductive components 12 disposed on the insulating body 11, a ground prong 13 disposed movably in the insulating body 11, a conductive ring 14 and an operating part 15. The conductive ring 14 reinforces an aperture 111 disposed at a front end of the insulating body 11, is sleeved on the ground prong 13, and contacts an outer surface of the ground prong 13 so as to connect electrically the ground prong 13 to a ground wire 16 that is coupled to a rear portion of the conductive ring 14. A sleeving portion 151 of the operating part 15 is sleeved on a rear end of the ground prong 13, and an operating portion 152 of the operating part 15 extends outwardly of the insulating body 11 via a guiding aperture 112 of the insulating body 11. The operating portion 152 is movable in the guiding aperture 112 so as to drive movement of the ground prong 13 between a retracted position (see FIG. 3), in which the ground prong 13 is received in the insulating body 11, and an extended position (see FIG. 2), in which the ground prong 13 extends outwardly of the front end of the insulating body 11 via the aperture 111.
The dual-mode electrical plug of the prior art has the following drawbacks. After a long period of use, friction generated between the conductive ring 14 and the outer surface of the ground prong 13 when the ground prong 13 is moved leads to wearing of the conductive ring 14 and the ground prong 13. Such wear leads to inadequate contact between the ground prong 13 and the conductive ring 14, and consequently, an inadequate electrical connection between the ground prong 13 and ground wire 16. Moreover, structural components of the dual-mode electrical plug are numerous, which incurs increased design and manufacturing costs. Therefore, it is desired to provide a dual-mode electrical plug having a ground prong that maintains an adequate electrical connection with a ground wire, and which can be designed and manufactured at a reduced cost.